d- lungimea drumului
I zi = a= 2/15 · d
a doua zi = b= 7/15 · d
a treia zi =60 km = d-a-b
d-2/15 d - 7/15 d=60
6/15 d=60
1/15 d=10
d=150 km
a=2/15 · 150=20 km
b=7/15 ·150=70km
Drumul are 150km, in prima zi a parcurs 20km, in a doua zi 70km, iar in a treia zi - 60km.